Views: 251 Author: Site Editor Publish Time: 2020-12-28 Origin: Site
Each valve is different in appearance, structure, and even functional use. However, the globe valve and the gate valve have some similarities in shape, and both have the function of cutting off in the pipeline, so there will be many friends who do not have much contact with the valve get confused about the two. In this article we will distinguish globe valves and gate valves from five aspects.
The structure of the gate valve will be more complicated than the globe valve. From the perspective of the appearance, the gate valve is higher than the globe valve and the globe valve is longer than the gate valve under the same caliber. In addition, the gate valve is divided into a bright rod and a dark rod, while the globe valve does not.
When the globe valve is opened and closed, the valve stem is raised, that is, when the handwheel is turned, the handwheel will rotate and lift along with the valve stem. The gate valve rotates the hand wheel to make the valve stem move up and down, and the position of the hand wheel does not change.
The flow varies, and gate valves require full opening or full closing, while globe valves do not. Globe valves have specified inlet and outlet directions, and gate valves do not have inlet and outlet direction requirements.
In addition, the gate valve has only two states of fully open or fully closed, and the route of the gate opening and closing is long, and the opening and closing time is long. The travel of the valve plate of the globe valve is much shorter, and the valve plate of theglobe valve can be stopped somewhere during the movement for flow adjustment. The gate valve can only be used for cut-off use and has no other functions.
The globe valve can be used for both shut-off and flow adjustment. The fluid resistance of the globe valve is relatively large, and it is more laborious to open and close, but because the distance between the valve plate and the sealing surface is short, the opening and closing route is short.
Because the gate valve can only be fully opened and fully closed, when it is fully opened, the medium flow resistance in the valve body channel is almost 0, so the opening and closing of the gate valve will be very labor-saving, but the distance between the gate and the sealing surface is long, and the opening and closing time is long. .
The gate valve has the same effect in both directions. There is no requirement for the direction of the inlet and outlet, and the medium can flow in both directions. The globe valve needs to be installed in strict accordance with the direction indicated by the arrow on the valve body. There is also a clear stipulation on the direction of the inlet and outlet of the globe valve.
The globe valve is low-in and high-out. From the outside, it is obvious that the pipeline is not on a phase horizontal line. The gate valve runner is on a horizontal line. The gate valve has a larger stroke than the stop valve.
From the perspective of flow resistance, the flow resistance of the gate valve is small and the flow resistance of the stop valve is large when it is fully opened. The flow resistance coefficient of the ordinary gate valve is about 0.08 ~ 0.12, the opening and closing force is small, and the medium can flow in two directions. The flow resistance of ordinary globe valve is 3-5 times that of gate valve. It must be closed forcibly when opening and closing to achieve sealing. The valve core of the globe valve only contacts the sealing surface when it is completely closed, so the abrasion of the sealing surface is very small. Due to the large flow resistance, the globe valve needs to be added with an actuator, and the torque control mechanism should be adjusted.
The sealing surface of the globe valve is a small trapezoidal side of the valve core. Once the valve core falls off, it is equivalent to the valve closing. The gate valve is sealed by the side of the valve disc. The sealing effect is not as good as that of a globe valve.